Pharmacokinetics, safety, and efficacy of mixed formulation of fosrolapitant and palonosetron (HR20013) in combination with dexamethasone in patients with solid tumors scheduled for highly emetogenic cisplatin-based chemotherapy: a phase I trial.

BACKGROUND

This phase I trial aimed to assess the pharmacokinetics (PK), safety, and preliminary efficacy of a single dose of HR20013 (mixed formulation of fosrolapitant and palonosetron) plus dexamethasone in patients with malignant solid tumors.

METHODS

Solid tumor patients who were naive to cisplatin-based chemotherapy and scheduled to receive the single-day cisplatin-based chemotherapy were enrolled. Patients would receive a single intravenous infusion of HR20013 (Day 1) before cisplatin-based chemotherapy, alongside oral dexamethasone (Day 1, 12 mg, once a day; Day 2-4, 3.75 mg, twice a day). Primary endpoints were PK parameters of fosrolapitant, rolapitant, M19 (a major active metabolite of rolapitant), palonosetron, and dexamethasone.

RESULTS

Twenty-four patients were enrolled, and 22 received study treatment. Fosrolapitant reached maximum plasma concentration (Cmax) immediately at the end of the infusion of HR20013 (1 h), followed by a short terminal phase, and it was completely hydrolyzed into rolapitant. Mean elimination half-lives of rolapitant and palonosetron were 188.2 and 51.5 h, respectively. M19 reached Cmax at approximately 166.2 h. After a single oral administration of dexamethasone at 12 mg, when combined with HR20013, dexamethasone reached Cmax at approximately 1.5 h, with a mean Cmax of 106.0 ng/mL. Treatment-related adverse events occurred in 54.5% of patients, with constipation (22.7%), increased blood pressure (18.2%), abdominal distension (13.6%), injection site reaction (9.1%), and increased neutrophil count (9.1%) being most common. Complete response rates (no emesis/rescue therapy) were 90.9% at the overall phase (0-120 h) and 86.4% at the beyond delayed phase (120-168 h).

CONCLUSIONS

HR20013 plus dexamethasone had a favorable PK profile, manageable safety, and durable antiemetic efficacy.

TRIAL REGISTRATION: ClinicalTrials.gov, NCT05465681.